Free carnitine, short-chain acylcarnitine and long-chain acylcarnitine will be measured in the plasma and urine under circumstances of spontaneous ketosis (fasting and diabetic) and induced ketosis (somatostatin infusion) in humans. The effects of glucagon and insulin administration will also be observed. Synthetic precursors of carnitine such as trimethyllysine and butyrobetaine will also be assayed in the urine.